Dial back for clocks and the like



1941- A. A. MARTIN 2,229,021

DIAL BACK FOR CLOCKS AND THE LIKE Filed April 4, 1939 ANGUS AMQA T/N Patented Jan. 14, 1941 UNITED STATES PATENT OFFICE DIAL BACK FOR. CLOCKS AND THE LIKE Application April 4, 1939, Serial No. 265,904

4 Claims.

The present invention relates to clocks and more particularly to an improved means for mounting the time movement supporting frame on the dial back of a clock or the like.

The aim of the invention is to provide an improved dial back and movement mounting frame having cooperating interlocking portions which facilitate rapid assembly of the dial back and frame without the use of tools or skill on the part of the workman, yet assure positively holding of the parts together after assembly.

A still further object is to provide a dial back for clocks which is simple and inexpensive to manufacture, is sturdy in construction, and can readily withstand any rough usage to which it may be subjected.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the accompanying drawing:

Figure l is a perspective view of a dial back and a frame member, illustrating an embodiment of the invention;

Fig. 2 is a fragmentary rear elevational view of the dial back;

Fig. 3 is an enlarged sectional view taken along the line 3-3 on Fig. 2, illustrating a leg for attaching the frame member to the dial back;

Fig. 4 is a side view of the leg;

Fig. 5 is a fragmentary view of the frame member, illustrating a preferred form of aperture for receiving the leg;

Fig. 6 is a fragmentary view similar to Fig. 5, illustrating the leg being inserted into the aperture;

Fig. 7 is a fragmentary view, illustrating the leg after having been inserted into the aperture and attached to the frame member;

Fig. 8 is a sectional view taken along the line 8-8 on Fig. 7;

Fig. 9 is a fragmentary view, illustrating another form of aperture; and

Fig. 10 is a fragmentary view, illustrating still another form of aperture.

Referring to the drawings in. detail, there is shown a dial back It! for a, clock or the like having means for receiving and supporting a front plate II of a frame upon which may be mounted the usual time movement of the clock. The dial back In is constructed of relatively stiff but slightly bendable sheet metal, of suitable thickness and may be in the form of a substantially circular disc having a centrally located aperture I2 and an offset aperture I3 through which the time hand and alarm operating shafts, respectively, are adapted to extend. As the time movements, operating shafts, etc. are not necessary for an understanding of the invention, a description and showing of the same has been omitted. The dial back I0 further is provided with a plurality of legs hi, usually three in number, which are stamped from the disc then bent inwardly and perpendicularly thereto and provide means for supporting the frame plate II in spaced relation with respect to the dial back.

In the embodiment illustrated the legs it are strengthened by providing at the junction of the leg and disc a longitudinal reenforcing rib or corrugation l5 (Figs. 3 and 4) stamped or pressed into the leg and partially extending into the disc. The ribs I5 add sufficient strength to the legs to prevent their being bent out of their perpendicular position and thus allow the dial backs to be made of thinner and less expensive sheet metal. As a result, the dial backs may be stored in bulk by being placed in bins or large boxes, and can be roughly handled without the danger of bending the legs out of place.

In order to mount the frame plate ii on the legs I4, the upper end portions of the legs It are adapted to extend through suitable apertures in the frame plate I I and then interlock into position. To accomplish this, the upper portions I6 of the legs M are twisted out of the normal plane of the leg, whereupon the outer free end is disposed at an angle between five and fifteen degrees to the normal plane of the lower untwisted portion thereof, and, when so twisted, the normal tendency of the metal is to return to the twisted position whenever bent therefrom. The outer or free end I6 of each leg I4 is provided with a half round or slightly tapered end surface It which functions more or less as a cam and tends to twist the upper portion of the leg into its normal plane of the lower leg as it passes through the cooperating apertures in the frame plate I I, as hereinafter described.

At one side of the legs I4 and at approximately the point Where the vertical side edge thereof is tangential to the round or tapered end surface I6, there is cut a transverse notch or recess I! having a width approximately equal to the thickness of the frame plate and a depth of approximately one-third the width of the leg; the notch serving to receive a portion of the frame plate to interlock and firmly position the frame on the legs, as hereinafter described. Below the notch is an outwardly extending shoulder portion I3 serving as an abutment to limit insertion of the leg into the amrture of the plate.

The frame plate I I is constructed in the usual manner, but the apertures 29 therein, which are adapted to interlock with the upper portion of the legs I4, are so cut that the major axis thereof is in normal alignment with the untwisted lower portions of the legs. Thus, when the frame plate is initially positioned over the legs in assembling the device, the upper ends or twisted portions I6 of the legs M will not coincide with the center line thereof but will be across a part of the aperture of less length necessitating the twisting of the upper portions of the legs towards the normal plane thereof before being capable of passing through the frame apertures. In the embodiment illustrated in Figs. 1, 5, 6, and 7, the apertures are shown as being diamond shaped and having oppositely disposed sides 2| and 2la. The major axis of the aperture along the center line L has a length slightly less than the width of the legs l4 below the rounded end I6 thereof, and a width or minor axis W which is less than the length L, whereby the distance between the opposing side edges 2| and Zia will likewise be less than the length L. The aperture is so cut that the length L thereof is in substantial alignment with the lower untwisted portion of the legs when the parts are assembled, and, therefore, makes an angle of between five and fifteen degrees with respect to the plane in which the upper portions iii of the legs are disposed.

In order to attach the frame plate H tothe dial back, the apertures 20 are positioned over the twisted upper end l6 of the legs, with the length L arranged in the plane of the untwisted portion, whereupon, as shown in Fig. 6, in dotted lines, the upper twisted portions N5 of the legs will be at an angle of five to fifteen degrees with the length L of the aperture and the rounded cam edges I6 will engage the oppositely disposed side edges 2| and 2 la thereof. As the plate I! is forced downwardly, the side edges of the aperture will tend to twist the upper portion of the legs into the normal plane of the untwisted portion to dispose the legs lengthwise of the aperture in the position shown by full lines in Fig. 6. The upper end of the legs will be so held until the frame plate I l is forced downwardly into alignment with the notches l1, whereupon the leg will spring to its normal or unstressed position, causing the base wall H] of the notch to engage one side edge of the aperture and the opposite edge of the leg to engage the opposite side edge. A portion of the plate II is also positioned within the notch, and the parts firmly interlock together.

In Fig. 9 a front frame plate is shown having an aperture 20 therein which is substantially oval and has sides 2 I adapted to act as cams for forcing the upper portion I6 of the leg into position to pass through the aperture.

In Fig. 10 another form of aperture 20" is shown, which is generally oval and has cam faces 2!" and recesses 23 at its end for permitting the upper portion it of the leg to pass through the aperture.

From the foregoing description, it will be seen that the present invention provides a stronger dial back which can be readily manufactured Without increase in cost. By reenforcing the legs, the dial backs can be stored in bulk without danger of damage thereto and the legs remain in proper position to be secured to the frame. The invention further provides an improved method of assembling and securing the dial backs to the frames which can be rapidly performed without the use of tools, thus saving a great deal of time and labor. When assembled, the dial backs and frames are securely locked and will not separate, even if subjected to rough usage.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is 1. In combination, a dial back having a plurality of legs extending substantially perpendicularly thereto, the free ends of said legs being twisted out of the plane of the lower portion thereof and each of said legs being provided with a transverse notch adjacent its free end, and a frame plate having a plurality of apertures through which said free ends of the legs extend, said apertures having a major axis of approximately the width of the legs and adapted to lie in the plane of the untwisted portions of the legs and a minor axis of less width than the major axis, whereby said twisted ends of the legs extend transversely of the apertures with a portion of said plate positioned within the notches.

2. In combination, a dial back having a disc and a plurality of legs extending outwardly from said disc and thereto, the outer ends of each of said legs being twisted slightly out of the plane of the leg and terminating in a tapered portion and provided with a transverse notch in one side thereof adjacent the tapered portion, and a frame plate having. a plurality of elongated apertures, each aperture having an axis of maximum length disposed at an angle to the twisted upper portion of the legs, whereby said twisted ends of the legs extend transversely of the apertures with portions of said plate positioned within the notches.

3. In combination, a dial back comprising a disc having a plurality of legs extending substantially perpendicularly thereto, each leg having a rounded free end twisted slightly out of the plane of the leg and a transversely extending notch adjacent said rounded end, and a frame plate having a plurality of elongated apertures therein each arranged in the plane of an untwisted leg portion, said twisted ends of the legs extending through and lying transversely of said apertures with portions of said plate extending into said notches, whereby the opposite sides of said apertures are engaged by one of the walls of the notches and by the opposite edges of the legs in alignment with the notches.

4. In combination, a dial back comprising a disc having a plurality of legs stamped outwardly therefrom and extending substantially perpendicularly thereto, said legs having a'reinforcing offset rib at the junction of each leg and the disc, a mounting plate carried on the outer ends of said legs, and cooperating interengaging means on the outer ends of said legs and on said plate for interlocking same in position.

ANGUS A. MARTIN.

substantially perpendicularly 

